Multiplex communications – Fault recovery – Bypass an inoperative station
Reexamination Certificate
1998-02-23
2001-03-06
Ngo, Ricky (Department: 2731)
Multiplex communications
Fault recovery
Bypass an inoperative station
C370S535000, C359S199200, C359S199200, C359S199200, C359S199200
Reexamination Certificate
active
06198721
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to a method for data transmission in a ring network and to a system suitable therefor. More specifically, the present invention is directed to a method for data transmission in a 2-fiber ring network with a plurality of network nodes wherein working signals are bidirectionally transmitted between terminal multiplexers and add-drop multiplexers on the ring network and wherein protection signals are bidirectionally transmitted over other parts of the ring network.
2. Description of the Prior Art
The report of the ICC '93 IEEE, 2/1993, pages 1245 through 1251 reveals optical communication networks with different ring structures that employ wavelength-division multiplex methods in signal transmission. Patent applications DE 43 37 089 A1, E 0651529 and E 0651528 A1 disclose optical ring networks wherein signal transmission occurs in a wavelength-division multiplex mode, whereby signals allocated to individual, specific wavelengths can be coupled out and coupled in. In a way which is known, these ring networks can be equipped with a monitoring ring in addition to what is referred to as a working ring.
The contribution “First results of an experimental Coloured Section Ring” in '22 European Conference on Optical Communication—ECOC-96”, Oslo, WeB.2.3, page 3.51 to page 3.54 reports about a ring structure that is shown in FIG.
1
. Such structure bidirectionally connects add/drop multiplexers, which neighbor one another, to one another via two light waveguides—one light waveguide being provided for each transmission direction. Only a single wavelength is used for the transmission between two add/drop multiplexers, whereas, however, different wavelengths are used on all other transmission sections.
The infeed and outfeed of signals occurs via optical add/drop multiplexers (OADMs) that correspond to optical filters (
FIGS. 3
,
4
and
5
). This structure was tested for SDH connections (Synchronous Digital Hierarchy). Modern data networks should both enable point-to-point connections of terminal multiplexers and enable the operation of add/drop multiplexers which are connected to one another in a ring-like fashion. An alternate circuit is absolutely required. Further, optimally short switchover times should be achieved in case of malfunction.
SUMMARY OF THE INVENTION
In an embodiment of the present invention, a method for data transmission in a 2-fiber ring network is disclosed wherein the network has a plurality of network nodes such that each network node contains a terminal multiplexer and/or an add/drop multiplexer, and wherein the method includes the steps of: bidirectionally transmitting first working signals between first and second terminal multiplexers of different network nodes via a first working connection over separate light waveguides on a first portion of the network; bidirectionally transmitting first protection signals between the first and second terminal multiplexers via a first protection connection on a second portion of the network wherein a first wavelength is employed for the first protection connection which differs from other wavelengths respectively employed for other protection connections between other terminal multiplexers; bidirectionally transmitting second working signals between first and second add/drop multiplexers of different network nodes via a second working connection over separate first and second light waveguides; and bidirectionally transmitting second protection signals between the first and second add/drop multiplexers via a second protection connection existing over the second portion of the network, wherein a second wavelength is employed for the second protection connection between the first and second add/drop multiplexers which differs from other wavelengths respectively employed for other protection connections between other add/drop multiplexers.
In an embodiment, the method further comprises the step of: transmitting and receiving both the first working signals and the first protection signals over the first wavelength.
In an embodiment, the method further comprises the steps of: supplying different wavelengths to respective connector modules of both terminal multiplexers and add/drop multiplexers via a plurality of wavelength-division multiplex units; providing a plurality of switch devices wherein each switch device is associated with a signal wavelength-division multiplex unit; and selecting a signal having a specific wavelength with each switch device.
In an embodiment, the method further comprises the steps of: providing a monitoring and control assembly in each terminal multiplexer and in each add/drop multiplexer; sensing a disrupted working signal with the monitoring and control assembly; and switching to a protection signal upon the sensing of a disrupted working signal.
In another embodiment of the present invention, a system for data transmission in a 2-fiber ring network is disclosed which includes a plurality of network nodes, first and second light waveguides connecting the plurality of network nodes wherein the first and second light waveguides respectively include opposing transmission directions, a plurality of terminal multiplexers and a plurality of add/drop multiplexers located at the network nodes, a plurality of wavelength-division multiplexer units wherein each wavelength-division multiplexer unit is located at a network node for the outfeed and infeed of signals having specific wavelengths, a plurality of working connector modules wherein each module is associated with either a terminal multiplexer or an add/drop multiplexer and wherein the working connector modules are bidirectionally connected to one another over both the first and second light waveguides, and a plurality of protection connector modules wherein each connector module is associated with a terminal multiplexer or an add/drop multiplexer and wherein the protection connector modules are connected to one another over a second part of the network.
In an embodiment of the system, corresponding working connector modules and protection connector modules receive and transmit signals having the same wavelength.
In an embodiment, the system further includes a plurality of switch devices wherein each switch device is provided in a wavelength-division multiplexer unit for selecting signals having a specific wavelength.
In an embodiment, the system further includes a plurality of monitoring and control assemblies wherein each assembly is located in an add/drop multiplexer for controlling signals.
Additional features and advantages of the present invention are described in, and will be apparent from, the detailed description of the presently preferred embodiments and from the drawings
REFERENCES:
patent: 5576875 (1996-11-01), Chawki et al.
patent: 5760934 (1998-06-01), Sutter et al.
patent: 5867289 (1999-02-01), Gerstel et al.
patent: 5943148 (1999-08-01), Hamel et al.
patent: 5986783 (1999-11-01), Sharma et al.
patent: 6046833 (2000-04-01), Sharma et al.
patent: 43 37 089 A1 (1993-10-01), None
patent: 0 651 528 A1 (1993-10-01), None
patent: 0 651 529 A1 (1993-10-01), None
patent: 0 716 521 A2 (1993-10-01), None
patent: 0 729 247 A2 (1996-02-01), None
patent: 0 743 772 A1 (1996-05-01), None
“First Results of an Experimental Coloured Section Ring”, A. Jamel et al., pp. 3.51-3.54.
“Multiwavelength Survivable Ring Network Architectures”, A.F. Elrefaie, pp. 1244/1251.
Bell Boyd & Lloyd LLC
Ngo Ricky
LandOfFree
Method and system for data transmission in a ring network does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and system for data transmission in a ring network, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and system for data transmission in a ring network will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2523691